The invention relates to a motor vehicle door latch, with a locking mechanism, furthermore with an activation lever system working on the locking mechanism, and with a locking element, which disables the activation lever system when acceleration forces of a specified magnitude occur, for example in the event of an accident.
Diverse types of motor vehicle locking systems or motor vehicle door latches due to centrifugal forces or relevant mass locks are known. Fundamentally, it involves preventing unintentional opening of the motor vehicle door equipped with the relevant motor vehicle door latch in the case of severe accelerations, as may occur in the event of an accident. Only thus can it be ensured that the passengers in the motor vehicle receive maximum protection and, for example, safety devices such as lateral airbags, etc. are activated accurately in the motor vehicle door.
In practice, a distinction is made between active and passive systems. Active systems are characterized by a movement occurring both for severe and slight acceleration of the latch kinematics or the motor vehicle door latch and in particular the activation lever system in order to attain safe functionality over the entire lifetime. On the contrary, passive systems only react in the case of unusually severe acceleration, i.e. in the case of accident.
All previously known centrifugal force or mass locks for the prevention of unintentional door opening in the event of a crash require additional components which increase the weight of the motor vehicle door and the cost. Thus, for example, within the scope of EP 2 133 496 A2 the pertaining external door handle is equipped with a pivotable locking element acting as a mass lock.
A corresponding handle can only be activated in a release position of the mass lock or the pivotable locking element. On the contrary, the handle is blocked in the case of a crash. The necessary and relatively complex locking element not only increases the mass of the known external door handle significantly, but considerable costs are also associated with it.
Although the class-specific state of the art in accordance with DE 10 2010 049 393 A1 also works with an additional locking element, this engages the locking mechanism directly and can consequently be of a compact and small construction. Furthermore, the activation lever system is not touched. Consequently, its functional safety is not impaired. However, an especially robust locking element is used which increases the weight of the known motor vehicle door latch overall.
It is therefore important overall not only to maintain the functional safety of the locking element throughout the entire lifetime of the motor vehicle door latch, but in the previous state of the art ultimately no convincing solutions have been provided which combine the opposing requirements of functional safety in conjunction with a light weight and reduced costs. Added to this is the fact that partly statutory requirements prescribe that the crash must be kept under control with the motor vehicle door latch in its unbolted state in particular. This is where the invention is used.